


The Swap

by Ereana



Category: Haikyuu!!
Genre: Domestic Fluff, Established Relationship, Fluff, Gen, Growing Up, M/M, Morning Cuddles, Nostalgia, OsaHina are so in love, Post-Time Skip, Pre-Time Skip, Time Travel
Language: English
Status: Completed
Published: 2020-08-15
Updated: 2020-08-15
Packaged: 2021-03-06 00:54:10
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,757
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25914679
Author URL: https://archiveofourown.org/users/Ereana/pseuds/Ereana
Summary: It's something everybody goes through at one point in their lives but Osamu is still a little surprised when it happens to him. He doesn't wake up in his big bed snuggled up against his boyfriend. No, instead he's greeted with the panicked shrieking of his brother, his-very-much-a-teenager brother. Great.Or Post-Time Skip Osamu wakes up in the Inarizaki group training camp and makes the best of it.
Relationships: Hinata Shouyou/Miya Osamu, Miya Atsumu & Miya Osamu
Comments: 41
Kudos: 553





	The Swap

**Author's Note:**

> This is the sappiest thing I have ever written.

They called it The Swap.

Well most people did. There was a really fancy complicated 15 syllable name that scientists like to use but for the average person it was just known as The Swap.

No-one knew exactly when it had started but again, apart from a small number of dedicated academics this wasn’t something your average member of the general public concerned themselves with.

All you needed to know was that at some point in your life you would wake up and you would be in your past self’s position for 24 hours and vice versa. The time differences varied from pensioners waking up in their childhood home to just last week. A little window of time travel that everyone experienced and no-one really knew why, again that small group of academics were working furiously on the issue.

There were limitations of course. The world would probably have been destroyed long ago if humans had the chance to change history willy nilly like that. Through experimentation and notes and a not insignificant amount of guesswork a rough structure of rules had been set down:

  1. You couldn’t change the past. If you tried to do anything that would change the future once you returned to your original time you wouldn’t remember anything about the 24 hours spent in the past. Any person you had interacted with would not remember meeting you or anything you.
  2. You couldn’t leave anything behind in the past or write any notes to people. It wasn’t known exactly what happened but it had been proven to be impossible.
  3. You physically went back in time, it wasn’t a mind switch, you would wake up in the psat 
  4. The past version of you wouldn’t remember much about their 24 hour trip to the future, they’d recall feelings, impressions, maybe a single image but nothing concrete. 
  5. The future/current version of you would remember the visit, so long as you didn’t break rule number 1.



There were speculations about what other rules there might be, some had as many as 20, but these were the y that everyone agreed on.

So when Osamu opened his eyes that morning and found that he wasn’t in his big king size bed with the morning sun shining through the window he wasn’t immediately alarmed. Instead of his usual resting place he’d woken up under a too small blanket staring at a ceiling that definitely wasn’t the one from his apartment. He pushed himself up and ran a hand through his hair, probably not a kidnapping as he was free to move and the window didn’t look locked.

“What the fuck!?”

Ah. Now that was a familiar voice. He ran a hand over his face to clear the last remnants of sleep from his eyes and turned his head. A pair of shocked brown eyes bore into his own and Osamu resisted the urge to snort at how surprised his brother looked; mouth agape and pointing at him like he was picking him out of a police lineup.

His surprised twin brother who looked like a teeanger and was already up and dressed in his Inarizaki tracksuit for the day.

The blanket that was now too small meant that his feet were sticking out and subject to the chilled morning air, the sleeping shirt he’d put on last night was the same and still hung a little loose around the shoulders. He flexed his hands and traced his eyes over the little cuts and scars that were the result of years working in a kitchen.

Probably not a dream then.

Not if Tsumu was in it anyway.

Speaking of Atsumu, his brother was still stuck frozen in a pose of shock and pointing at him accusingly.

“Yer face is gonna get stuck like that y’know.” He said letting his eyes wander over the room; plain, simple, he’d spent enough time here as a teenager to remember what this was. The presence of two other sleeping teenagers only confirmed it.

Honestly it was amazing that Atsumu’s yell hadn’t woken them but Riseki and Gin had both been able to sleep like logs and nothing short of an earthquake could rouse them, not even a group of 4 bored teeangers drawing on their faces with markers. Riseki had been pretty pissed but after Gin had nearly strangled Suna a ban had been put on any further sleeping pranks.

“Samu, is that you? And what the hell’s wrong with my face?!”

Osamu stretched and let out a sigh of relief. He was too old to be sleeping on floors anymore. “Apart from the fact I have to look at it? Anyway, it’s not that hard to figure out is it? I’ve been swapped.”

Leaving Atsumu to splutter in peace he reached for the phone laying at his side, Let’s see if Riseki was here then he was at least in the second or third year of high school which meant his password was….

The phone unlocked and Osamu stared at the date.

10 years. 10 years in the past, all the way back to 2013. His third year of high school which meant that this was most likely the last training camp before the upcoming interhigh. Not only that but this was the camp that they had shared with-

A yelp from another part of the building cut through his thoughts and he set the phone down. Well, best to make the most of this right?

“Do ya know where Coach Oomi or Coach Kuroso are? Think i’ll need to borrow some clothes.” It was a fairly reasonable request in his humble opinion but Atsumu was gawking at him like he’d just turned purple and started a limbo competition. “Unless of course yer brain is still processing all this?”

“Shut up!” There’s nothin’ wrong with my brain. Ugh, just wait here I’ll go find one of them.” Ah insults, the fastest way to snap Atsumu out of whatever funk he was in. The true language of siblings. Atsumu sprinted out the door and the noises of screams, yells and crashes followed soon after.

Osamu rubbed his neck and wondered how long he had to enjoy the silence.

“O-Osamu-kun, is that you?”

Not long.

The rest of the morning was similarly loud and chaotic. His old teammates kept staring at him with poorly hidden curiosity, it was so annoying that Atsumu had started to snap at anyone who looked too long. It was awkward as hell too, he was a 28 year old man not a teenager anymore and he would have preferred to avoid the others if he could but Atsumu and Suna insisted he stay in view at all times.

Normally he wouldn’t give in to the whims of a pair of brats but he was tired and it wasn’t as bad with Suna and Atsumu as it was with some of the others.

Things improved a little when he helped out making breakfast and got to see the awe and delight on everyone’s faces when they took a bite of their meal. Honestly, those kinds of looks were one of the reasons he loved what he did. Seeing people enjoy the food he had made, how happy it made them, warmed something inside him. He was proud of what he did for a living.

Besides feeding a bunch of rowdy teenagers had nothing on the Wednesday afternoon lunch rush.

He could feel Atsumu watching him the whole time. Right, this was after they’d had their argument at the end of second year. He wondered what his brother was looking for. Some trace of sadness or regret that he had stopped playing? If so he was going to be disappointed. The day he’d opened his first restaurant had been the day he’d known that he’d made the right choice. Volleyball had been exciting and fun but it never came close to the rush and joy of working in his own restaurant and looking out to see a full house of hungry customers with smiles on their faces.

Or maybe not. He chanced a glance at Atsumu as he served up another plate. His brother didn’t look angry or upset; he looked....thoughtful as he stared down at the food in front of him. Maybe he’d seen the grin on Osamu’s face as he worked with what he loved and was wondering what caused it? Maybe he could tell how comfortable Osamu looked and understood why he’d chosen to walk away.

Atsumu saw him looking and looked away with a ‘hmph’. The effect was only a little ruined by the amount of food he had in his mouth making him look more like an annoyed chipmunk.

Or maybe Osamu was overthinking this. It was just 24 hours, not like anything there was anything he could do that would change anything,

Of course, it’s a training camp so other teams are attending as well. He ends up helping with breakfast for all of them and freely offers his help for lunch and dinner. The managers looked at him with stars in their eyes but he waved away their thanks. It’s the least he can offer after all the help they give to their teams.

The others look at him as well, he’d be surprised if they didn’t really. There are two teams from Hyogo whose names he can just about remember, a team from another prefecture that one of them had invited along with them, and of course Inarizaki’s guests Miyagi’s own Karasuno.

They’re easily the loudest group in the food hall, which is saying something given that it’s a room full of hungry teenagers, and he’s pretty sure at one point their Libero goes flying across the room. They stare at him like everyone else but the captain at least, Ennoshita something he thinks, manages to keep them from bothering him.

He turned back to the oven and tried to ignore the gaze he can feel piercing into his back.

He doesn’t join for practice. He had two more meals to prepare and besides, he would just run any semblance of teamwork Inarizaki had at the moment. It’s not like he can just slot seemingly into place like a shiny new gear. The old him will just have to practice double tomorrow, he knows because he remembers Atsumu telling him so when he returned from the future.

So he stepped back. He observed. He smiled and choked back fond laughter at the startling reminder of his high school days when life was so different and the future was a scary uncertain thing. When he hadn’t known if he was making the right choice or if he and Atsumu would ever really recover from what he’d done by choosing to walk away.

Yeah, he’d been a pretty foolish kid.

It wasn’t like either of them would have let the other just leave like that.

He took the opportunity to thank both coaches for their efforts and bit back a laugh at how shocked Coach Oomi looked at his words. Had he really changed that much?

Lunch rolled around and the happy looks of people eating good food returned with it. The compliments were loud and he’s pretty sure most of his team have caught on to what he does for a living. Not like it was a secret anyway.

Suna looked at him like he wasn’t sure if he’s allowed to say anything about it, eyes flickering over to Atsumu, before he shrugged and said how good it was that at least one of them had decent life skills. Osamu laughed as Atsumu turned on their friend and snapped back something about how lazy Suna was in practice that morning.

Oh if they only knew.

Rintaro Suna - middle blocker for the division 1 EJP Raijin volleyball team.

That wasn’t something that was achieved by being lazy. He had to hand it to Suna though, he’d hidden just how much he was committed to the sport really well. Osamu had been sure the only guy who’d go pro along with Atsumu was Aran but both Suna and Riseki had made it to V1.

Monsters the lot of them.

Osamu covered his mouth to hide the smile that was forming. Ahh, this was no good. He’s not supposed to be a nostalgic sort of guy. The kitchen called to him and he left the two to their squabble.

He determinedly doesn’t look when Atsumu bites into his onigiri, the one Osamu had spent months developing to make sure his annoying brother didn’t have any complaints about it when he tried it for the first time. It’s one of the staples of his menu now, the special tuna onigiri that his brother always orders after a game.

Shit. When did he get so sentimental.

“You ok Atsumu-senpai? Ya look a little off?”

“I-It’s nothin’ just eat yer food. Don’t let any go to waste.” 

This time when he glanced back Atsumu was the one watching him. His face, the face Osamu knows better than his own, was carefully blank but Osamu has always been able to read him and a smile tugged at his lips.

Yeah.

Yeah still his favourite. 

He wondered if Atsumu understood the message of what that simple plate of food represents.

_ I’m still here. _

Then again there isn’t anyone who can read him as well as Atsumu so he doesn’t have anything to run about.

Honestly he should have expected Atsumu to corner him at one point. He’s working on dinner when a voice cuts through the air.

“So ya really did it huh?” He doesn’t need to look around to see who it is.

“Gonna have to be a little more specific baby brother.”

“Wha! I’m the older one asshole! Ma confirmed it and it’s on the birth certificates an everythin!”

“Technically I’m 28 and yer only 18 so if ya do the math I’m the older one right now.” He washed his hands in the sink, mind already whirling with what to serve this evening. “Though ya always did suck at math.”

“Fuck off. I don’t wanna hear it from the guy who thought Russia was a continent.”

“Maths is way more important than Geography anyway.”

“How the hell are you meant to be a successful chef if ya don’t know the places where food comes from?”

He turned to face his brother letting the sentence hang in the air for a moment. The air felt charged, he could almost feel it snapping.

“I mainly stick to Japanese food anyway. Dabbled a bit in Brazillian actually which was fun?” The last bit seemed to throw Atsumu for a second before he shook his head and crossed his arms in the captain-stance they’d both practiced after seeing Kita use it so effectively. 

“Brazilian? Why would….Never mind. Just so ya know I’m gonna make the teenage you practice double tomorrow for missing today. No way am I letting Karasuno leave without one last ass kicking.”

“I seem to recall they won a few matches against us here. Kageyama-kun improved quite a bit after coming here. Nice of ya ta take him under yer wing.” Atsumu flushed red and stomped his foot.

“I did no such thing. Besides we have to beat them at their best ya know. Was a disgrace they didn’t make it to the first Interhigh. They have to make it to the Spring one so we can get our revenge.”

They do make it.

Karasuno will be there as the Miyagi representatives and they’ll face Inarizaki in the third round. This time Inarizaki will win. It’ll be another heart racing three set match that will come down to the wire. Neither team able to clinch the last set until the end when the balance swung in the foxes favour.

It’s the year Inarizaki win it all and the last time Osamu plays an official volleyball match.

The rules of The Swap are absolute so Osamu shrugged and returned to his food prep.

“Yeah, yeah that’s for past me to worry about. Now scram, ain’t right for the captain to skip out on practice.”

“I ain’t skippin’ ya jerk.” He could hear the huff and just knew that Atsumu was pouting. “Whatever, with or without ya we’re gonna beat em now.” 

A pause. He heard footsteps head in the direction of the door before stopping.

“I guess that onigiri wasn’t completely terrible.” The door slammed shut and along Osamu allowed himself to laugh.

Foolish brother, he never was good at being sincere.

Dinner was as well received as lunch and breakfast and this time Osamu is the one who is shooed away. Apparently attempting to clean up after cooking three full meals for 5 teams of teenagers was a step too far.

All in all the day hasn’t been awful.

He was really looking forward to waking up in his own bed though.

“Guah!”

Now who could that be.

He walked around the corner and blinked at the scene in front of him. Two boys from the other guest team are looming over a certain tiny middle blocker from Karasuno. They’re clearly up to something, maybe bitter from how handily the crows beat them in the morning match, and Hinata looked panicked.

Yeah he hadn’t really grown confident outside of the court until the end of his third year if Osamu is remembering right.

Well, it’s not like he would let this go even when he was young.

“Now what do we have here then?”

All three of them jumped. The two troublemakers in particular looked about two seconds from fleeing now that they were no longer alone with their prey. 

Osamu smiled. It wasn’t a very nice smile. It was the one he reserved for pushy customers who made bogus complaints to try and get free food or treated his staff like shit.

“U-Uh we were just helping this kid out and-”

“Hey I’m not a kid!”

Atsumu cut them all off with a cutting motion through the air.

“Don’t care about yer excuses, get back to yer own team.” Nobody moved. “Now.” The two bolted, not pausing to even look at their would-be target before dashing all the way down the corridor. 

Cowards.

He hadn’t even raised his voice.

“Wow, they moved a lot faster than they did on the court.” The words and the slightly disapproving tone that goes along with them caused him to snort.

“Yeah, maybe they should work more on their skills than ambushing guys outside of bathrooms.”

Hinata smiled at him and bounced, actually bounced over. 

“Thanks for your help Osamu-san. Are you going to sleep already? I didn’t see you clearing up after dinner-NOT THAT YOU SHOULD! You’ve been cooking all day and it was so good and bwah! Just ignore me please.”

Osamu chuckled and hoped that he doesn’t look as fond as he feels.

Yes he remembered this training camp in particular very well. He and Hinata had grown pretty close during the week, each having to deal with their own troublesome genius setter and-

“No worries, I’m glad you enjoyed the food.”

“Are you kidding? It was amazing! And supper tasty. Everyone wanted seconds.”

“I’m glad.”

There’s something a little shy in the way Hinata was looking at him. It’s reminiscent of the surprised shock on Atsumu’s face when he woke up today but softer a little closer to awe.

“You looked like you were having a lot of fun today. I don’t think I’ve ever seen you smile so much.”

That was true. He’d learned to be more open, more expressive after high school. It was easier to express himself and without Atsumu’s constant presence he had to learn how to communicate better with people who couldn’t read him in one glance.

“Ya think so? Well it was a lot of fun.”

“Yeah! You look like Atsumu-san does when he’s playing against us.”

How observant.

“Well we do have the same face. Ya still havin’ trouble tellin’ us apart?”

Hinata turned bright red and waved his fists around in embarrassment, His voice came out just on the side of shrill. 

“That was one time! Ugh, why did I tell you that? Also you’re not dying your hair anymore? Or won’t do or will not or I don’t know?”

“Na, too much hassle to keep up.”

“It looks nice.”

“Thank ya.”

He needed to end this quickly otherwise his mask was going to crack. 

“Anyway, ya best get back to yer team, they’re probably organising a rescue party as we speak and I’m in no mood to deal with all ya pesky crow friends.”

Hinata giggled and nodded. “I don’t blame you, even the new first years think I need protecting.”

“That might have somethin’ to do with yer decision to challenge every single powerhouse player to a duel to the death with yer eyes.”

“I don’t!” A worried ‘Hinata-senpai!’ interrupted them and Hinata looked a little annoyed. “Speaking of, I better go. It was nice to see you future Osamu-san. I hope that we’re still friends in the future. I’ll see past you tomorrow then.”

Oh if he only knew.

Osamu managed to wave and watched the boy run off towards his panicked rescuers.

He wanted to sleep. Let tomorrow come and pull him back to where he belongs.

Tomorrow, when a younger more unsure Osamu will finally pluck up the courage to ask Hinata for his number after Atsumu swears he’s not letting him on the bus ride back unless he does something about ‘those stupid pinin’ heart eyes ya keep starin at him with’.

Tomorrow, when the same Hinata Osamu had just saved from yet another unfortunate bathroom meetup will gladly hand over his number and Osamu will try not to read too much into light blushes or shy glances or the way they both slightly linger trading phones as their hands brush.

Tomorrow held a lot for the pair of them.

He fell to sleep with relative ease, mind peacefully drifting into dreams of memories and tomorrow and things that stay the same and the things that change.

The ceiling he woke up to is familiar. It’s his. The bed is a bit harder to place because it’s the one they have in their spare room.

Then again it made sense that this would be where the younger him would sleep. His own memories from that time are blurry, as to be expected, but he remembered feeling happy and excited and an incredible feeling of relief for reason’t he couldn’t place. What happened here while he was back in the past?

Only one way to find out.

The apartment is just as he left it. There are some dishes in the sink waiting to be washed but he ignored it in favour of making a quick cup of coffee. His feet are eager to carry him somewhere else but Osamu has learned when to be patient.

The burst of caffeine helped to wake up the last drowsy parts of his brain. His phone was full of texts but he only replied to one.

_ I’m back _

**About time asshole. Younger you was annoying, wouldn’t leave me alone for nearly the whole day >:(**

Osamu smiled.

The light felt warm on his skin and he wandered towards the balcony, taking in the furniture and photos on the wall all the signs of a life well lived. Younger him is really lucky but then again so is he, the future is always there after all.

The door to the balcony is open and he stopped just before crossing the threshold letting his eyes wander over the figure in front of him.

Shouyou was always up before him, if Osamu was lucky sometimes he would catch him like this; sat on his yoga mat in the morning sun, eyes closed, perfectly at peace in the world.

He almost hated to interrupt such a calming scene.

Almost.

Shouyou didn’t tense when Osamu wrapped his arms around him, pulling his boyfriend’s smaller frame back into his chest and burying his head against his neck.

A hand reached up to stroke his hair and he sighed with pleasure at the gentle touch.

“Hey, was wondering when you’d get back.”

“Just woke up now, missed ya.”

Shoyou chuckled and wriggled deeper into the hug. This close Osamu can feel every exhale and inhale, if he really concentrated he could make out the steady beat of Shouyou’s heart, beating nearly as fast as his own.

“I missed you too. Younger you was nice but I think he was a little embarrassed about waking up in the same bed as me.”

Embarrassed right. Partly because of the whole bed sharing thing and partly to do with the fact that Hinata Shouyou at 28 was one of the most unfairly attractive men that Osamu had ever seen. Playing volleyball professionally had its perks after all.

No wonder he’d wanted Atsumu around as he probably wouldn’t have been able to say two words to Hinata without getting distracted by his arms, or his legs, or his chest, or his smile, or any part of him really.

Then again he was biased.

“Want me to make breakfast?”

“Not just yet, I need to finish this up but  _ someone _ is stopping me.” Osamu held him tighter.

“In a minute. I didn’t get any Shouyou cuddles yesterday.”

“Poor Samu, must have been terrible for you.” Hinata hadn’t stopped stroking his hair and Osamu wanted to stay like this forever, basking in the affection of the man he loved and the heat of the morning sun.

It’s a good thing The Swap forbade people from changing the past or spoiling the future.

It meant Osamu didn’t have to worry about putting all of this into words. 

How was he supposed to describe their warm little apartment, bright and cozy, where they hosted friends and family and rang with the sound of Shoyou’s laughter?

How to accurately convey the fulfilment of a dream of food, of service of pride in his work and coming home every day with a wonderful sense of satisfaction. 

Shouyou squirmed in his lap until Osamu loosened the hug enough for him to swivel round and face him.

His heart thumped harshly in his chest.

Shouyou is looking at him and smiling. To Osamu he’s brighter than the sun and it almost hurts to meet his gaze.

He loves this man. So much.

How to describe a relationship that while not always easy had become a cornerstone of Osamu’s life?

How does he talk about that first kiss after his last nationals. The phone calls, the texts, the long hours of train journeys over to Miyagi, and the yearning that was only soothed when they were back in each other’s arms.

How did he explain Brazil?

The fear of being left behind. The pride in what his partner was trying to achieve. The video calls at 3am because Shouyou was struggling and Osamu was half a world away but they could still talk, they could still laugh and pretend for a moment that they’re with each other.

No, not easy but always always worth it.

How can he articulate waiting at Tokyo airport at 6am, tired and thirsty, and watching Shouyou exit the arrivals tunnel. How good it felt to just hold him again. Taking careful note of all of the changes; the tan, the hair, the muscles and the things that stayed the same; the laugh, the eyes, the quiet way ‘I love you Samu’ was spoken against his mouth. Hinata’s hands running over him, learning Osamu’s own changes and reminding themselves of old habits; this is how Shoyou likes to be kissed, that’s the spot where Osamu was ticklish, this is how they relearn to love one another.

The Black Jackals.

The Olympics.

Back to Brazil, then another world famous team, and another.

He fell in love with a man who would chase volleyball all over the world.

But Shouyou always came home. Back to Japan, back to Osamu.

It’s a good thing he couldn’t talk about the future because 24 hours wasn’t long enough to tell even a fraction of it.

Shouyou was still smiling at him and Osamu knew what he wanted.

They needed to make breakfast and he had to go check on the restaurant and who knows what Atsumu got up to yesterday but that’s all secondary.

In the soft light of the morning Osamu kissed Shouyou and was back where he belonged.

**Author's Note:**

> So apparently when I stopped writing for 4 years all the fic ideas just built up and up and now that i'm writing again they're all hitting me at once OTL. I love these two and I hope that I did them justice. This is my first time writing from Osamu's POV and hopefully it turned out ok. The end was pure self-indulgent fluff but I'm happy that I wrote it.
> 
> Any comments or kudos are greatly appreciated and thank you so much for taking the time to read this. Feel free to come say hi on [twitter](https://twitter.com/Jen_B93) if you want.


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